Inefficient collection methods, insufficient coverage of the collection system, combined with improper disposal of municipal solid wastes and contaminated sources of water supply, are major threats to public health and environmental quality in DCs. Although these threats have been evident for several years, historically, pollution control and environmental management have been given little or no attention in many DCs. On the other hand, governmental policies have concentrated on industrial development. Recently, however, environmental quality in many urban areas in DCs has deteriorated to such a degree that it can no longer be ignored. This situation has resulted in a substantial concern and intensification of efforts to find and apply methods of reversing the trend and of raising environmental quality to an acceptable level.